Activation of NMDA and non-NMDA receptors by L-aspartate in the suprachiasmatic nucleus of the rat.
The receptors mediating the responses of neurons in the rat suprachiasmatic nucleus (SCN) to focal application of L-aspartate were studied in coronal slices by whole-cell patch clamp electrophysiology. Neurons in the SCN showed inward currents in response to both L-aspartate and L-glutamate. Responses to L-aspartate were only partially blocked by D-2-amino-5-phosphonovalerate (D-AP5) and by 10 mM Mg+2 at resting membrane potentials, suggesting an action upon-NMDA glutamate receptors. The remaining currents were blocked by the quinoxalines CNQX (6-cyano-7-nitroquinoxaline-2,3-dione), DNQX (6,7-dinitroquinoxaline-2,3-dione), and NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline1), indicating an action of L-aspartate upon non-NMDA receptors. We conclude that cells in the SCN are among the relatively few types in which an action of L-aspartate upon non-NMDA receptors has been demonstrated.
Brautigan
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RA
Department of Biology, Georgetown University, Washington, DC 20057, USA.
Eagles
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DA
D000818:Animals; D001224:Aspartic Acid / Q000819:agonists / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018091:Receptors, AMPA; D011956:Receptors, Cell Surface; D016194:Receptors, N-Methyl-D-Aspartate; D001224:Aspartic Acid; D018698:Glutamic Acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid